U.S. Patent Publication No. 2009/0236017, entitled “Forming of Metallic Glass by Rapid Capacitor Discharge”, is directed to a method of rapidly heating a metallic glass sample and shaping it into an amorphous article using a rapid discharge of electrical current, where a quantum of electrical energy is discharged through a metallic glass sample having a substantially uniform cross-section to rapidly heat the sample to a processing temperature between the glass transition temperature of the metallic glass and the equilibrium melting temperature of the glass forming alloy and simultaneously or subsequently shaping and then cooling the sample to form an amorphous article. Other U.S. Patent publications are also related to the rapid heating and shaping an amorphous articles by discharge of electric current, including: U.S. Patent Publication No. 2012/0132625, entitled “Forming of Metallic Glass by Rapid Capacitor Discharge Forging”, U.S. Patent Publication No. 2012/0255338, entitled “Sheet Forming of Metallic Glass by Rapid Capacitor Discharge”, U.S. Patent Publication No. 2013/0001222, entitled “Forming of Ferromagnetic Metallic Glass by Rapid Capacitor Discharge Forging”, and U.S. Patent Publication No. 2013/0025814, entitled “Injection Molding of Metallic Glass by Rapid Capacitor Discharge”. Each of the foregoing publications is incorporated herein by reference in its entirety.
The Rapid Discharge Heating and Forming (RDCF) process involves rapidly discharging a quantum of electrical current across a metallic glass feedstock via electrodes in contact with the feedstock in order to rapidly (e.g. on the order of 500-105 K/s) and substantially uniformly heating the feedstock sample to a temperature conducive for viscous flow. Once the heated feedstock reaches that desired viscous state, a deformational force is applied to the heated and softened feedstock to deform the feedstock into a desirable shape. The feedstock sample may be shaped into an amorphous bulk article via any number of techniques including, for example, injection molding, dynamic forging, stamp forging, blow molding, etc. The steps of heating and deformation are performed over a time scale shorter than the time required for the heated feedstock to crystallize. Subsequently, the deformed feedstock is allowed to cool to a temperature substantially close to the glass transition temperature, typically by contact with a thermally conductive shaping tool such as a metal mold or die, in order to vitrify it into an amorphous article.
There remains a need to develop an automated apparatus for RDHF to allow large-scale production of amorphous articles by the rapid discharge heating and forming technique.